Theory and experimental study for sliding isolators with variable curvature     

Lyan‐Ywan Lu  Shih‐Wei Yeh 《地震工程与结构动力学》2011,40(14):1609-1627

Because a conventional isolation system with constant isolation frequency is usually a long‐period dynamic system, its seismic response is likely to be amplified in earthquakes with strong long‐period wave components, such as near‐fault ground motions. Seismic isolators with variable mechanical properties may provide a promising solution to alleviate this problem. To this end, in this work sliding isolators with variable curvature (SIVC) were studied experimentally. An SIVC isolator is similar to a friction pendulum system (FPS) isolator, except that its sliding surface has variable curvature rather being spherical. As a result, the SIVC's isolation stiffness that is proportional to the curvature becomes a function of the isolator displacement. By appropriately designing the geometry of the sliding surface, the SIVC is able to possess favorable hysteretic behavior. In order to prove the applicability of the SIVC concept, several prototype SIVC isolators, whose sliding surfaces are defined by a sixth‐order polynomial function, were fabricated and tested in this study. A cyclic element test on the prototype SIVC isolators and a shaking table test on an SIVC isolated steel frame were all conducted. The results of both tests have verified that the prototype SIVC isolators do indeed have the hysteretic property of variable stiffness as prescribed by the derived formulas in this study. Moreover, it is also demonstrated that the proposed SIVC is able to effectively reduce the isolator drift in a near‐fault earthquake with strong long‐period components, as compared with that of an FPS system with the same friction coefficient. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Shaking table test and analysis method on ultimate behavior of slender base‐isolated structure supported by laminated rubber bearings     

Eiji Takaoka  Arinori Nimura 《地震工程与结构动力学》2011,40(5):551-570

This paper describes the results of shaking table tests to ascertain the ultimate behavior of slender base‐isolated buildings and proposes a time history response analysis method, which can predict the ultimate behavior of base‐isolated buildings caused by buckling fracture in laminated rubber bearings. In the tests, a base‐isolated structure model weighing 192 kN supported by four lead rubber bearings is used. The experimental parameters are the aspect ratio of height‐to‐distance between the bearings and the shape of and the axial stress on the bearings. The test results indicate that the motion types of the superstructure at large input levels can be classified into three types: the sinking type; the uplift type; and the mixed type. These behaviors depend on the relationship between the static ultimate lateral uplifting force on the superstructure and the lateral restoring characteristics of the base‐isolated story. In the analysis method, bearing characteristics are represented by a macroscopic mechanical model that is expanded by adding an axial spring to an existing model. Nonlinear spring characteristics are used for its rotational, shear, and axial spring. The central difference method is applied to solve the equation of motion. To verify the validity of the method, simulation analysis of the shaking table tests are carried out. The results of the analysis agree well with the test results. The proposed model can express the buckling behavior of bearings in the large deformation range. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Morlet小波显著性检验和精度分析在地磁场和地震活动性周期分析中的应用   总被引：3，自引：0，他引：3       下载免费PDF全文

尹继尧  朱元清  宋治平  张国民  薛艳  刘杰 《地震学报》2011,33(5):663-671

首先通过对加入随机噪声的合成信号进行Morlet小波变换并进行显著性检验, 分析所得信号的周期成分的显著性和非显著性, 然后研究信号周期长短、 信号观测时间段长短与精度之间的关系．在此基础上,以活动周期比较稳定的太阳黑子活动作为实例分析,结果显示本文的精度分析和显著性检验方法对于周期谱的精度和显著性研究是可行的．最后将该方法应用于全球地震活动周期谱的分析,求出全球地震活动周期谱及其显著性与精度．研究结果表明,在利用Morlet小波分析地磁场和地震活动性周期时引入显著性检验,并结合本文给出的精度, 可以从数据中提取出周期谱及其显著性和精度．   相似文献   

离散元微观参数对砂土宏观参数的影响   总被引：2，自引：0，他引：2  

申志福  蒋明镜  朱方园  胡海军 《地震工程学报》2011,33(Z1)

采用离散元商业软件PFC2D对密砂和松砂试样共进行了66组双轴压缩试验,试验中改变颗粒接触刚度和粒间摩擦系数以探究离散元微观参数对试样宏观参数(弹性模量和内摩擦角)的影响,其中颗粒法向刚度变化范围为1.5×108～1.5×109N.m-1,粒间摩擦系数变化范围为0.1～0.7 N.m-1。结果表明:颗粒接触刚度对弹性模量有一定程度影响且对密样影响程度大于松样,而对内摩擦角基本无影响;粒间摩擦系数对试样弹性模量有明显影响且对松样的影响程度更大,对密样和松样的内摩擦角都有非常显著的影响。  相似文献   

钢-混凝土高层结构抗震性能振动台试验研究     

黄襄云  曹京源  马玉宏  徐丽  陈建秋  吴迪 《地震工程与工程振动》2011,31(2):68-74

广州天誉大厦采用型钢混凝土框架一钢筋混凝土筒体的混合结构体系,地面以上结构采用抗震缝兼伸缩缝分隔为南、北塔两个独立结构体系,南塔高186.5 m,北塔高159.5 m.两塔的核心筒总宽度与核心筒总高的比值均超出了规范限值.为研究这种超限高层混合结构的抗震性能,对其进行了缩尺(1/30)模型的振动台试验,并建立了有限元计...  相似文献   

钢管混凝土框架-混凝土核心筒减震结构振动台试验研究     

周云  任凤鸣  范华冰  张季超 《地震工程与工程振动》2011,31(2):130-137

某超高层钢管混凝土框架-混凝土核心筒结构因指标超限在设计中采用了耗能减震技术,为了检验该减震结构的抗震性能,制作了1/35的缩尺模型,通过在钢管混凝土框架设置阻尼器或不设置阻尼器,进行模拟地震振动台对比试验,研究了模型结构的动力特性和不同烈度地震作用下的加速度、位移和应变响应。研究结果表明:地震作用下,该钢管混凝土框架-混凝土核心筒减震结构与钢管混凝土框架-混凝土核心筒结构相比,位移、加速度和应变响应均有一定程度的降低;罕遇地震作用下,通过设置耗能减震构件,层间位移角最大值从超过规范要求的1/84减低至满足规范要求的1/130,表明该减震结构具有更优良的抗震性能。  相似文献   

复杂退台高位转换高层建筑振动台试验与分析     

马玉宏  韩富平  黄襄云  陈建秋  谭平  李冰冰 《地震工程与工程振动》2011,31(5):75-83

对一幢具有转换层的复杂退台式框架剪力墙高层建筑的1/35缩尺模型进行了模拟地震振动台试验,深入研究该结构的动力特性和地震反应特征.试验及理论分析表明:该结构的抗震性能基本满足现行规范要求;由于结构上部逐渐退台,因而结构顶部有较明显的鞭端效应;结构首层和结构转换层及其相邻层的剪力墙、转换层上下层柱是受力较大的区域,应当局...  相似文献   

基于小波变换的补燃循环火箭发动机模态参数辨识     

杜飞平  谭永华  陈建华 《地震工程与工程振动》2011,31(4):150-157

文中阐述基于小波变换的结构模态参数辨识方法的基本原理.首先介绍Heisenberg测不准原理,该原理限制了时频能量的同时集中.因小波变换的窗口可以随信号特征不同而变化,符合实际信号的要求.然后论述利用小波脊线的方法识别单自由度和多自由度系统的模态参数的理论.将该方法应用于某型补燃循环液体火箭发动机模态参数辨识中,得到了...  相似文献   

福州地震台TJ-2型体积式应变仪安装及注水试验     

林国元 《华北地震科学》2011,29(1):53-56

在安装福州地震台TJ-2型体积式应变仪过程中,发现存在钻孔选点与观测室分开考虑等问题,提出一些建议。井孔注水试验结果揭示,该井孔探头顶部可能存在一个与探头近距离的含水层干扰。初步对气压、水位、降雨影响进行分析。  相似文献   

山西运城东郭井水温梯度测试及其结果分析     

刘国俊  杨海祥  张小红  黄春玲 《山西地震》2011,(2):10-11,21

山西运城东郭观测井是山西省"十五"项目新建的地下流体物理观测井,于2007年10月12日进行数字观测正式产出资料。根据"十五"前兆台网《SZW-1A型数字式温度计(V2004)》安装条件要求,2007年12月25日对观测井进行了一次水温梯度测试,目的是了解该井井水温度背景值,确定水温观测部位,明确井筒中的热系统与含水层的关系,为下一步分析水温微动态提供参考依据。  相似文献